Cleaning and cooling system for photographic printing apparatus



CLEANING AND COOLING SYSTEM FOR PHOTOGRAPHIC PRINTING APPARATUS Filed Nov. 14, 1967 P 1969 s. P. JEFFEE ETAL 3,466,995

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ruemosrn 46' INVENTORS SAUL P. JEF'l-EE GUS LIMNIOS A T TORNEYS United States Patent 3,466,995 CLEANING AND COOLING SYSTEM FOR PHOTO- GRAPHIC PRINTING APPARATUS Saul P. Jelfee, Scarsdale, N.Y., and Gus Limnios, Washington Township, N.J., assignors to Movielab, Inc., New York, N.Y., a corporation of New York Filed Nov. 14, 1967, Ser. No. 682,943 Int. Cl. F24f 13/00, 3/14, 3/16 U.S. Cl. 98-33 6 Claims ABSTRACT OF THE DISCLOSURE A closed-loop cleaning and cooling system for lamp houses for photographic printers located in an air conditioned room. Air for cooling lamps in the lamp houses of the printer is distributed from a separate air conditioner from the room air conditioner. Dust and dirt are prevented from entering the room by eliminating negative pressure and developing a slight positive pressure relative to the ambient to cause air to flow outwardly from the room. Lamp life in the system is extended many times the usual lamp life.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to photographic printers and more particularly to air cleaning and cooling means for the lamp housing of such printers.

Description of the prior art In the photographic printing art, especially in respect to printers of multi-color film, the ambient air conditions must be controlled and maintained within narrow limits of temperature, humidity and cleanliness in order to satisfactorily print or reproduce film with uniform results and at substantially continuous operating conditions.

The art of printing has evolved to a state wherein accurate printing or both black and white and color film with uniform results can be achieved. To use modern film to achieve such results, it must be processed within very narrow ranges of operating and environmental ambient conditions. For example, the light energy that is needed for the printing of film should be uniformly constant. Furthermore, the combination of the optical components, such as the filters and lamps, requires calibration which can be upset by changes in temperature, humidity and accumulation of dust and dirt on the surfaces of the lighttransmitting components. For example, the problem known as lamp smoke-out results from the coating of dust and oil vapors which adhere to the surface of lamps and change thereby, the color .balance and intensity whereby the optical field is uneven and sub-standard photographic prints result. Further serious problems in the printed film occur if the relative humidity varies above or below the limits of 60-65%. Below a relative humidity of 60% static charges develop causing the characteristics static discharge markings to be printed on the film thereby ruining it. When the relative humidity exceeds 65% the emulsion tends to become sticky.

Present day film requires an ambient environment of relative humidity that is within the range of 60% to 65% Such relative humidity conditions are easily maintained with existing air conditioning equipment. It becomes dif ficult, however, even for the most capable air conditioning equipment to maintain these humidity conditions when the ambient varies widely, such as occurs during high-humid days with access doors to the printing room being repeatedly opened. It is well known, thus, that such a state of p7 3,466,995 Ice: Patented Sept. 16, 1969 varying conditions, known as variable loading, makes the problem of printing film to obtain uniform results very difiicult.

As indicated above, photographic printing systems must be calibrated in order to print with uniform results. The calibration of such equipment is very time consuming and costly, and any alteration in the calibration that is effected, for example, by an accumulation of dust, alters the film product to the extent that it is practically worthless. It is to be appreciated, therefore, that the effect of dust on the lamps and other optical components is a critical problem.

It is a practice in this art to select high energy lamps (750-1200 watts) so that they can be operated at lower voltages than the rated voltage of the lamp, whereby an extended life of the lamp is obtained and yet sufficiently satisfactory to provide the light required for printing film. Usually, such -a procedure has produced remarkably long-lived lamps. In this Way, the uniform light output from a given lamp may be reasonably expected to operate for the usual requirements in the printing art. Nevertheless, the accumulation of dust on the lamps is compensated for by increasing the operating voltage of the lamps and thereby shortening their expected life. Dust accumulating on such lamps, however, aggravates the calibration problem.

It is thus well known and is to be here understood that temperature, humidity and dust are significant problems in the art of printing photographic film. It is also to be appreciated that much effort, without success, has gone into minimizing, if not tolerating, the effects of either the presence or variations of such ambient conditions.

In order to overcome the harmful effects of dust that collects on the surface of the lamps, filters and other critical optical apparatus of the printing machines, a very rigid schedule of cleaning and other preventive maintenance, such as the replacement of lamps, must be followed. Such a procedure is a necessity and a large expense in this industry. A full day during a weekend must even be set aside, according to such schedules, in order to carry out such cleaning and maintenance procedures. Since most film processing facilities are operated on a 24-hour-a-day basis for five and even six days, year-in and year-out, it will be appreciated that down-time caused by emergency breakdown of lamps or alteration or deviation in the calibration of the critical light requirements, is very costly if not disastrous to the business of processing film and meeting schedules.

Heretofore, printing machines were housed in rooms that were air conditioned by the usual known techniques. In such rooms, the air is circulated through condensing and filtering apparatus to remove dust and regulate humidity of the air and to further cool or add moisture to the air according to the humidity requirements. The printing apparatus used in this art, as has been indicated above, comprises heat producing lamps. -In order to keep the room at tolerable and even operating temperatures, the lamps require cooling facilities as by blowing air over their surfaces. Accordingly, heretofore as well known in this art, the lamp housings of printing machines were provided with high capacity blowers rated for 600 to 750 cubic feet per minute to blow relatively cool room air from the room and pass it over the surface of the lamp and exhaust it either directly into the room or through passages independent of the room, as through a passage to the atmosphere. Applicants have discovered that this mode of cooling the lamps has developed a negative pressure in the room relative to the surrounding ambient. This negative pressure creates a suction to the ambient surrounding the room whereby dust from the surroundings is carried into the room through any leakage paths, or door openings that occur.

It is the general object of this invention, therefore, to eliminate the negative pressure and the effects thereof in a photographic print room and to overcome the problems of dust and heat that relate to the lamp houses of such printers.

SUMMARY OF THE INVENTION According to the invention, we provide an air cooling and cleansing system that is independent of the air conditioning system of the room in which the printing machines are located. A common manifold or supply duct carries cooled and cleansed air discharged from a common air conditioning apparatus and distributes the sotreated air through a common manifold by separate feeders to each of the lamp houses of the printing machines. The air, on passing through the lamp housing is heated and is discharged into a return feeder to a common manifold for return to the cooling and cleansing apparatus for recycling and reconditioning the air.

The circulation of the air in the closed-loop system is usually effected by a large fan or impeller or the like. Accordingly, in the event of breakdown of the main supply fan, it is preferable to provide an emergency fan or blower in the separate feeders to inhibit an excessive rise in temperature in the event of a breakdown of the entire system. A thermostatic control is included in the air cooling and cleansing system for regulating the temperature of the air.

We have discovered that the usual humidity control is adequate if the room air conditioner maintains a relative humidity of approximately 62% to 65% and the room temperature of 74-76 F.

It will be appreciated that if the temperature of the incoming air to the lamp housing is low, relative to the dew point of the air, condensation will occur. Nevertheless, under the usual practices of conditioning the room air, to satisfy the critical requirements of the film manufacturers, we have found no difficulty in respect to condensation.

The use of our invention has shown remarkable improvements in increasing the life of a lamp by a factor as little as 4 to l and as much as 24 to 1. Thus, a lamp which has heretofore been expected to last under the usual prior art operating conditions of a printing process at 24 hours a day, of from two to five days, can now be expected, with our invention, to last from six to eight weeks.

One embodiment of the invention as illustrated by the attached drawing will now be described.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a block diagram schematic showing the relative arrangement of the components of the printing room and the separate air conditioning systems of our invention; and

FIG. 2 is a diagrammatic perspective view of the air cleaning and cooling system for a printer shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, there is shown in FIG. 1 the system of our invention in block diagram form. A room is provided with a plurality of photographic printers, 12-1, 12-2, etc. The room 10 is provided with an air conditioner 16 of conventional design arranged to maintain the temperature and relative humidity of the room within prescribed limits. Ducts 61 carry air from the room 10 into the air conditioner 16 and ducts 60 carry cooled and cleansed air back into room 10. A separate air cooling and cleaning apparatus 30 of custom design is arranged to clean and cool the air supplied to the lamp housing of the printers. The conditioner 30 may be located entirely within the room 10 or preferably may be located in a position external to the room 10. The conditioner 30 is provided with an inlet manifold 32 supplied by feeders 24-1 and 24-2, etc., from the discharge or outlet aperture of the respective lamp housings of printers 12-1, 12-2, etc. Inlet manifold 32 carries the heated air and any dust carried or suspended in the air from the respective lamp houses of the printers to the inlet of the conditioning apparatus 30 wherein the air is cleaned and cooled. The clean and cool air is discharged from the conditioner 30 to the output manifold 28 and distributed to inlet feeders and 22 communicating with the inlet aperture of the respective lamp houses of the printers 12-1, 12-2, etc.

Referring to FIG. 2 showing a perspective view of one printer feeder within the system which is illustrated in FIG. 1, it is noted that the corresponding numbered parts of the system as shown in the block diagram found in FIG. 1 are shown in perspective and pictorial detail in FIG. 2. We illustrate only one printer (12-1), but it will be understood that a plurality of such printers, 12-2, 12-3, etc., are contemplated and included in such systems as may be needed or desired. The inlet feeder 20 of air to the lamp housing 36 from the discharge manifold 28 is a conduit or hose being preferably flexible to allow for easy access and replacement of equipment. The feeder 20 is connected to the input of a blower or fan 42. The discharge or outlet of fan 42 is connected through hose or coupling 44 to the input aperture of the lamp housing 36 of printer 12-1 as at 44a. The lamp housing 36 is provided with conventional components such as a lamp 38 and filters and lenses 40. The film and associated apparatus that is in the printer machine (12-1) adjacent to the lamp housing 36 is not shown, but is of conventional design.

The exit or outletlaperture 24a of lamp housing 36 is connected to feeder 24-1, formed of a suitable hose or tubing, also perfectly flexible, which, in turn, is connected to the discharge manifold 32 at aperture connection 24b. The air from the lamp house 36 is carried in the discharge manifold 32 to the conditioning apparatus 30 comprising dust and dirt filters 50, fan 48, cooling coil 52 and heat exchanger 54 and is returned to the output manifold 28. A thermostat 46 senses the temperature of the air in manifold 28 by probe 46a to regulate the temperature of the air in the lamp house air conditioning system in a known manner.

The air-flow passages comprising the air conditioner apparatus 30 and the connecting hose and manifolds just described are sealed substantially from the ambient environment of the room and its air conditioning system and thus is independent of the conditions in the room. Any dust that may be in the closed-loop system comprising the lamp housing is separated and removed therefrom by filters 50.

In operation, fihn is processed through each of printers 12-1, 12-2 wherein lamps 38 in lamp houses 36 of the respective printers cause the air circulating therein to be heated from an air inlet temperature of 62 F. to an air exhaust temperature of F. The heated air is carried to the conditioner 30 through the input manifold 32 which, in turn, receives the heated air from each printer through the respective feeders 24-1, 24-2. The air passes through conditioner 30 wherein it is cleaned of any dust therein by filters 50, cooled by coils 52, and discharged to manifold 28 by fan 48. The air from manifold 28 is distributed to each printer through its respective feeder 20 and hose 44 connected in an air-tight manner to the lamp housing 36. Electrically-operated fan 42 supplements'the conditioner blower 48 by developing a slight pressure rise to blow the air into and through the lamp housing 36.

The air temperature of the air being circulated in the closed-loop containing the lamp houses is regulated to a heated temperature of approximately 90 F. at the discharge aperture of lamp houses and a cooled temperature of approximately 62 F. at the discharge of the conditioning apparatus 30. The temperature within room 10 is maintained within 74-76 F. by its air conditioner 16.

The relative humidity is kept within the limits of 62-65% based on a dry bulb reading of 74-7 6 F.

The pressure relative to the ambient atmospheric pressure is affected by the room air conditioning 16 and the closed-loop air conditioning system containing the lamp houses 36. In the operation of these two air conditioning systems, according to the invention, the not effective pressure in the room 10 is slightly positive relative to the surrounding ambient pressure. A positive room pressure causes air leakage to be outward from the room to the ambient surrounding the room and carry any dust or dirt that may be suspended in the air away from the room and, thereby, the printers situated in the room.

It will be appreciated that according to this invention, we have eliminated the negative pressure that is developed in a room heretofore provided with a simple air conditioning system in combination with air blowers or fans arranged to draw air from the room to cool the lamp houses and be exhausted to the ambient surrounding the room. In such prior systems the negative pressure developed by the simple exhaust blowers increased with each printer that was added or introduced into the room. We have discovered, as noted supra, that the negative pressure caused air leakage into the room and thereby carried dust and dirt suspended in such air into the room and thus be deposited subsequently on the optical components in the lamp houses of the printers.

It will be appreciated, further, that according to our invention, lamps 38 in the lamp houses are cooled by the relatively cool air supplied from the manifold 28 at a temperature of 6065 F. We have discovered that the life of lamps 38 has been increased by a factor of four and as much as 24 times over the expected life of similar lamps operating under prior systems utilizing a simple blower as discussed above. In such a prior system, the temperature in the lamp houses reached 110 F. within a room regulated by air conditioning to temperatures of 70-74" F.

The life of a lamp operating in a system of our invention, it will be still further appreciated, will be increased by operating the lamp at voltages below its rated voltage as is the practice in this art, but for longer periods of time owing to the absence or substantial absence of dust on the surface of the lamp, optics, and color filters.

From the foregoing description of our invention, it will be apparent that we provide a novel air cooling and cleaning system for lamp housings of printing machines situated in an air-conditioned room. This system, it will now be appreciated, maintains the pressure and temperature of the air independent of the ambient conditions of the room whereby no negative pressure relative to the surrounding ambient pressure is developed. According to the invention, therefore, the obviation of negative pressure and the provision of a positive pressure in the room, virtually eliminates the deleterious supply of dust from the areas surrounding the film processing room. Furthermore, any dust that is within the room is rapidly removed by filtering and the air is thereafter maintained in a cleaned and temperature-regulated condition.

It should be understood that this invention is not limited to the specific structures described and many modifications and different forms can be used in the structure disclosed as will be understood by those skilled in this art, without departing from this invention.

Having described our invention, what we claim is:

1. A method of operating a room containing a plurality of photographic processing apparatus, each of said apparatus having a housing for a high intensity light source for supplying the light energy for printing, comprising the steps of:

(a) regulating the temperature and relative humidity of the air in said room within selected limits;

(b) pressurizing the room slightly above the atmospheric pressure of the ambient surrounding the room by supplying an excess of air into said room;

(c) regulating the temperature of the air surrounding said high intensity light source to maintain a constant condition in a closed loop conduit system, separate from the air in said room by (1) supplying relatively cool air to said housing, 2) exhausting relatively warm air from said housing, and (3) cooling said relatively warm air in said closed loop system, whereby the net pressure in said room causes an outward flow from said room of air and any dust that may be suspended in said air and whereby the air in said room does not contact said light source.

2. The method according to claim 1 comprising the additional step of removing dust from the air within said closed-loop conduit by means of a filter disposed in said conduit.

3. The method of claim 1 wherein the temperature in said room is regulated to within the limits of and 74 degrees F. and the relative humidity is regulated within the limits of 60 and 65%.

4. The method of claim 1 wherein the temperature of the air supplied to said lamp housing is approximately 62 F.

5. The method of claim 1 wherein an air-conditioning device having a dust filter is included in said closed-loop conduit for said regulation of the temperature of said air in said conduit and for removing dust that may be suspended in said air.

6. A system for producing positive pressure in a room for processing photographic film comprising in combination:

(a) a room for processing photographic film;

(b) a plurality of photographic printers in said room, each of said printers having a lamp housing having an inlet and an outlet port for the passage of air therethrough;

(c) means for regulating the temperature and humidity of said room within prescribed limits, including fan means for supplying air into said room under pressure;

(d) a closed-loop conduit for passing air from the outlet to the inlet of said lamp houses;

(e) means in said conduit for regulating the temperature of the air in said conduit and for removing dust that may be suspended in said air;

(f) fan means for circulating air in said conduit under pressure whereby the net atmospheric pressure in said room causes an outward flow from said room of air and any dust that may be suspended in said air.

References Cited UNITED STATES PATENTS 2,855,839 10/ 1958 Teigen. 3,143,952 8/1964 Simon. 3,199,432 8/ 1965 Brandi. 3,263,400 8/1966 Hoke et a1 9833 X LLOYD L. KING, Primary Examiner 

